Re: A82: Display port question


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Re: A82: Display port question



Unless you have the right delays between writes you can not be sure what
the controller will do. So if you remove the call 7f3h's it might draw a
line, but you can not be sure and it might not draw in the correct spot.

The problem in your program seems to be that you do not call 7f3h before
the last write.

Dines

_______________________________________

Dines Justesen
Email: dines@post1.com or
       c958362@student.dtu.dk
WWW  : http://www.gbar.dtu.dk/~c958362/
_______________________________________

On Mon, 24 Nov 1997, Doug Torrance wrote:

> Hello, I'm trying to figure out how to write directly to the display
> port.  I'm having troubles, however.
> 
> ld a,$20
>  call $7f3
>  out ($10),a
>  ld a,$80
>  call $7f3
>  out ($10),a
>  ld a,$ff
CALL $7F3 :!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
>  out ($11),a
> 
> I thought this code would draw a line on the screen, however it does
> nothing.  If I take out the call $7f3's, it draws a line sometimes,  but
> not everytime.  What am I doing wrong?
> 
> Thanks!
> 
> --
> Doug Torrance
> profzoom@earthling.net
> http://profzoom.home.ml.org
> (:  Have a happy day!  :)
> 
> 
> 


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